64th International Symposium on Molecular Spectroscopy June 22 – 26, 2009 Millimeter Detection of AlO (X 2 Σ + ): Metal Oxide Chemistry in the Envelope of VY Canis Majoris E.D. Tenenbaum and L.M. Ziurys Department of Chemistry Department of Astronomy Arizona Radio Observatory, Steward Observatory University of Arizona

64th International Symposium on Molecular Spectroscopy June 22 – 26, 2009 Small Number Statistics and Interstellar Chemistry Over 140 interstellar molecules (and similar number of chemical models) Only a handful of astronomical sources carefully studied  Are we “missing” sources with different chemistry ??? Circumstellar Material: C-Rich shells principally observed (IRC+10216) Oxygen-rich shells neglected A closer look at O-rich envelopes  Circumstellar gas of O-rich Supergiant Star VY Canis Majoris (VY CMa) Spectral Line survey in 1 mm band (210 – 285 GHz) First comprehensive study of O-rich circumstellar environment Observed IRC for comparison 10 " Envelope of VY CMa

64th International Symposium on Molecular Spectroscopy June 22 – 26, 2009 Prime Time at the ARO Submillimeter Telescope Arizona Radio Observatory (ARO) operates: - Submillimeter Telescope (SMT) -12 m at Kitt Peak Installed new 1 mm receiver at SMT Utilizes ALMA Band 6 mixers Achieve noise levels of 3 mK ( 1 sigma) 12 m SMT 1 mm insert

64th International Symposium on Molecular Spectroscopy June 22 – 26, 2009 Collected data in 1 GHz sections 3 year project using over 2000 hours in telescope time ARO 1 mm Survey of VY CMa and IRC PhD Thesis E.Tenenbaum

64th International Symposium on Molecular Spectroscopy June 22 – 26, 2009 RAW Data: SMT at 1 mm No baseline subtraction No smoothing No other manipulations 30 hours integration AlO: N = 7→ 6 H 2 O maser 7 years of work at the SMT…. but look at the Spectra !

64th International Symposium on Molecular Spectroscopy June 22 – 26, 2009 Observations of AlO (X 2 Σ + ) Two 1 mm transitions: N = 7 → 6 and N = 6 → 5 at and GHz Observed with SMT One 2 mm line measured with the 12 m at 153 GHz (N = 4 → 3) Different line profiles  Al hyperfine structure: varies with frequency  Free radical Lab spectrum from Yamada et al. (1990)

64th International Symposium on Molecular Spectroscopy June 22 – 26, " Arc I Arc II CNT (Ziurys et al Nature) VY CMa: Complex Source Spherical wind - inner flow with narrow linewidths - outer flow with full expansion velocity Blue/Red-shifted outflows blue red

64th International Symposium on Molecular Spectroscopy June 22 – 26, 2009 Line Parameters of Observed AlO Transitions Transition ν (MHz)ΘbΘb V LSR (km/s)T A * (mK) N = 7  ± 57 ± 2 N = 6  ± 63 ± 1 N = 4  ± ± 0.5 AlO N tot ~ 2 × cm -2 T rot ~ 230 K f (AlO/H 2 ) ~ Linewidths of ~ km/s  Accounts for HF components in profiles Identical to NaCl: θ s ~ 0.5“ Inner part of spherical flow at r ~ 30 R *

64th International Symposium on Molecular Spectroscopy June 22 – 26, Log r (cm) R*R* R1R1 Star Dust Shell Acceleration Zone V exp ~ 15 km s -1 T ~ 1000 K cm -3 T ~ 25 K 10 5 cm -3 UV Molecules created at LTE near stellar photosphere (T ~ K) For AlO (r ~ 30 R * ): near photosphere Implications for Circumstellar Chemistry Observed Abundance of AlO But AlOH And Al 2 O More Abundant !

64th International Symposium on Molecular Spectroscopy June 22 – 26, 2009 And Even More Aluminum… AlOH also identified in VY CMa Emission weaker than AlO  More than LTE chemistry Shocks disrupt condensation process into Al 2 O 3 Lab spectrum from 1993 (Apponi, Barclay and Ziurys)

64th International Symposium on Molecular Spectroscopy June 22 – 26, molecules in VY CMa (OH, NH 3 ) Spectrum dominated by SO 2, SiO, SiS What else ?? New molecules in O-rich circumstellar gas:  AlO, PO, AlOH First time metal oxides and hydroxides seen in interstellar molecules Oxygen-rich Circumstellar environment fosters different chemistry Relate to grains, shocks, and photospheric molecules Electronic Bands of AlO observed in stellar atmospheres Conclusions and Future Directions AlO: A → X V4332 Sgr COCNCSHCNHCO + HNC SO 2 SiSSiONSH2SH2SH2OH2O SOPNPONaClAlOAlOH

64th International Symposium on Molecular Spectroscopy June 22 – 26, 2009 NSF Astronomy NASA Astrobiology